Basic refractory furnace structure



ug. 13, 1968 w, R, McLAlN 3,396,684

BASIC REFRACTORY FURNACE STRUCTURE Filed Oct. l0, 1966 Clie/ni l2 cal/yv Bonded Direct Bonded 8 l2 r l 36 3a 3a 24 4 3o 32 9&1 I

nvvE/vrok United States Patent O 3,396,684 f BASIC REFRACTORY FURNACESTRUCTURE William R. McLain, Chicago, Ill., `assignor to United StatesSteel Company, a corporation of Delaware Filed Oct. 10, 1966, Ser. No.585,425 8 Claims. (Cl. 11B-99) ABSTRACTH THE DISCLOSURE A basicrefractory furnace structure. particularly an r This invention relatesto a basic refractory furnace structure and more particularly to an openhearth furnace roof such as shown in Parker et al. Patent No. 3,013,510dated December 19, 1961. As shown therein vertical steel tie plates areprovided between some of the rows or courses of brick. Two types ofbasic brick have been used in such roofs-chemically bonded and directbonded. However, roofs made of chemically bonded basic brick failprincipally due to peeling of the bricks and roofs made of direct bondedbrick fail from peeling and because the tie plates oxidize and melt.Also, there is danger of the direct lbonded brick expanding7 andbreaking the furnace support binding. A direct bonded basic brick is onein which there is substantial direct attachment of the magnesia to thechrome ore without an interrupting film of silicate.

It is therefore an object of my invention to -provide a basic refractoryfurnace structure made of a combination of direct bonded and chemicallybonded bricks arranged in such a manner that the life of the furnacestructure is greatly increased over that of a similar structure madeentirely of either type of brick.

Another object is to provide an open hearth furnace roof which has adecreased cost per ton of steel produced in the furnace.

These and other objects will be more apparent after referring to thefollowing specification and attached drawings, in which:

FIGURE 1 is a view of a furnace roof taken longitudinally of the span ofthe arch;

FIGURE 2 is a view taken on the line II--II of FIGURE l;

FIGURE 3 is a view taken on the line III-HI of FIGURE 1;

FIGURE 4 is a plan view of a standard metal clad basic brick; and

FIGURE 5 is an elevation of the brick of FIGURE 4.

Referring more particularly to the drawings, reference numeral 2indicates an open hearth furnace having a front wall 4 and a back wall6. Buck stays 8 at the front and rear walls extend upwardly abovefurnace roof and are connected .at their tops by means of channels 12extending longitudinally of the span of the roof. Channels 14 extendingtransversely of the span of the roof also connect the upper parts of thebuck stays 8. A plurality -of rods 16 extend transversely of the roofspan and are spaced apart longitudinally of the span. The rods 16 aresuspended by means of hangers 18 from bars 20r supported on top of thechannels 12. The rods 16 pass through holes 22 in steel tie plates 24which extend longitudinally of the roof span. Skew back bricks 26 are3,396,684 Patented Aug. 13, 1968 supported by means 28 at the front andrear of the furnace. The roof 10 is shown as a ribbed ring arch in whichthe larger bricks, 30, making up the ribs, are arranged in two coursesor rows, one on each side of the plates 24. Two courses of smallerbricks 32 are arranged between the bricks 30. The bottom of the plates24 are shaped to conform to the bottom of the arch of the roof and thetop of the plates 24 have notches 34 therein with the notches 34 of eachplate 24 being aligned with the notches in the adjacent plates. A beamor rail 36 extending transversely of the span of the roof rests in eachset of aligned notches 34. Jacks 38 attached to the `top tie channels12. lare used to hold the beams 36 down against the plates 24 and thebricks 30 or in case of a plain ring arch against the bricks in all ofthe rings. The plates 24, in addition to suspending the brick, alsoserve to maintain the arch contour. It is preferred that the bricks 30and 32 be clad with metal sheets 39` in the usual manner.

The parts so far described are conventional and are essentially as shownin the above identified Parker et al. patent. It will be understood thatthe construction described is illustrative and may be varied. Accordingto my invention the bricks 30 in the courses on each side of the plates24 are chemically bonded basic brick and the bricks 32 in the coursesbetween the bricks 30 are direct bonded basic brick. The chemicallybonded basic bricks have `a modulus of rupture at 2300 F'. of 200 to 300lbs. per sq. in. and the direct bonded basic brick, at the sametemperature, a modulus of rupture of 1200i to 1600 lbs. per sq. in. Theanalyses of the two types of brick are as follows with all figures beingin percentage -by weight:

Chemically bonded Roofs have been provided on open hearth furnacesaccording to my invention and the indications are that the roof lifewill be increased by 50%.

While one embodiment of my invention has been shown and described itwill be apparent that other adaptations and modifications may be madewithout departing from the scope of the following claims.

I claim:

1. A basic refractory furnace structure comprising a plurality ofcourses of direct bonded basic brick, a plurality of courses ofchemically bonded basic brick, at least some of said courses of directbonded basic brick abutting courses of chemically bonded basic brick, atleast some of said courses of chemically bonded basic brick beingarranged in pairs, and a steel tie plate between the courses of thepairs of courses of chemically bonded basic brick.

2. A basic refractory furnace structure according to claim 1 in whichsaid courses of direct bonded basic brick are arranged in pairs betweensaid pairs of courses of chemically bonded basic brick.

3. A basic refractory furnace lstructure according toY claim 2 in whichsaid bricks are encased in steel plates.

4. A basic refractory furnace structure according to claim 1 in whichsaid structure is a furnace roof and the bricks are oblong in crosssection with their long dimension generally vertical. Y

5. A basic refractory furnace structure according to claim 4 in whichsaid courses of direct bonded basicbrick are arranged in pairs betweensaid pairs of courses of chemically bonded basic brick.

6. A basic refractory furnace structure according to claim 5 in whichsaid bricks are encased in steel plates.

7. A basic refractory furnace structure accordingto l claim 6 includingmeans for rigidly holding said tie 15 FREDERICK KETTERER, PrimaryExaminer.

plates in position.

8. A basic refractory furnace structure according to claim 7 in whichVsaid means for rigidly holding said tie plates in position includesbeams above said roof, and rigid means connected to and extendingbetween said beams and tie plates.

References Cited UNITED STATES PATENTS

